Forcella Sestier

Overview

Forcella Sestier is a genuine monster of a climb, one of those rare ascents where the sheer length is as intimidating as the gradient. Over 37.8 km the road hauls you from a valley floor at just 54 m all the way up to 2097 m at the summit — a net elevation gain of 2043 m. On paper the average gradient of 5.4% sounds almost civilised, but that number hides a savage truth: with a maximum pitch of 27.67%, this climb is anything but consistent. Rated HC (hors catégorie, the hardest classification above categories 1 through 4), it demands respect from the first pedal stroke.

How the Gradient Unfolds

The 5.4% average is a statistical illusion. Across 37.8 km, a climb this long inevitably includes flatter stretches, false flats, and possibly short descents that drag the mean down. What the average cannot tell you is where the pain lives. With ramps reaching 27.67% — more than five times the average — the difficulty is front-loaded into a handful of vicious pitches that will spike your effort far beyond anything sustainable. The gap between the total ascent of 2287 m and the net gain of 2043 m confirms there is 244 m of climbing that comes back down along the way, meaning you regain and lose altitude repeatedly. Expect the road to undulate rather than climb in a single clean line.

Pacing Notes

On a climb of 37.8 km, discipline beats bravado every time. Your single most valuable tool is a firm grip on your FTP — riding the shallow sections at or slightly below threshold, then accepting that the 27.67% ramps will punch you well into the red no matter how you meter the effort. Do not chase power on those spikes; survive them and settle back down. If you are unsure of your current threshold, run the numbers through the FTP estimator before you commit to a pacing plan. With 2043 m of net gain ahead, going out too hard in the first third is the classic way to blow up long before the 2097 m summit.

Gearing

Gear for the 27.67% max, not the 5.4% average — that is the golden rule here. A compact 34-tooth inner chainring paired with a 34×32 cassette is the sensible starting point for strong climbers, but on pitches this steep most riders will be far happier reaching for a 34×34 to keep the cadence spinning rather than grinding. On a 37.8 km effort, every extra tooth you can spare on the cassette pays dividends late in the climb when your legs are hollow. If your bike can take a wide-range setup, take it.

Summary

Forcella Sestier is a rare beast: HC-rated, brutally long, and topped by ramps that verge on the absurd. Come with a plan, come with the right gears, and come with patience.

Length: 37.8 km
Average gradient: 5.4%
Max gradient: 27.67%
Start: 54 m
Summit: 2097 m
Net gain: 2043 m
Total ascent: 2287 m
Category: HC